Stud mounted rocker and spring



Jan. 31, 1967 G} P. HA NLEY 3,301,238

STUD MOUNTED ROCKER AND SPRING Filed Feb. 1, 1962 INVENTOR.

Gaye P f/o/zfzy ATTORNEY United States Patent 3,301,238 STUD MOUNTED ROCKER AND SPRING George P. Hanley, Northville, Mich. assignor to General Motors Corporation, Detroit, Mich, a corporation of Delaware Filed Feb. 1, 1962, Ser. No. 170,329 4 Claims. (Cl. 123-90) This invention relates to internal combustion engines, and more particularly to rocker mechanisms for actuating valves, fuel injectors or other reciprocated parts thereof.

In such engines, there has been increasing use of rockers which are fulcrumed on individual supporting studs which are anchored at one end in the engine cylinder head and have their other end extending through a suitably large opening at the rocker fulcrum to accommodate the rocking movement of the rocker. For simplicity, journaling of the rocking movements of the rocker is effected by sliding an annular bearing member over the extended end of the stud and securing it thereto with a nut, the bearing member and opposing thrust face of the rocker having generally spherically shaped mating surfaces which also allow the rocker to rotate about its stud.

It is the principal object of this invention to improve such rocker arrangements, particularly in regard to biasing rocker movement in one direction and preventing rotation of the rocker about its stud. I have found that the rocker supporting stud serves uniquely for securing the fixed end of a cantilever spring whose face end extends along and resiliently bears against the rocker, the point of engagement of the spring with the rocker varying in distance from the stud as the rocker is rocked against it to provide a varying biasing force on the rocker. The arrangement is also well adapted to so arranging such a cantilever spring of the multileaf type, wherein increased deflection of the spring brings into play additional leaves of the spring for an even greater increase in biasing effect at the upper limit of rocker movement. Also, by employing rockers of upwardly presenting channel section with the cantilever spring engaging the web of the channel, rocker rotation about the stud can be effectively limited by having the fixed end of the spring secured against rotation by the stud. Such rotation of two rockers which rockably operate in unison can be also prevented by oppositely inclining their push rods and rigidly interconnecting the upper ends of the push rods at their pivotal connections with the rockers.

These and other objects and advantages of the invention will be readily understood from the following description of the structure shown in the drawing, wherein:

FIG. 1 is a transverse sectional view through the upper portion of an internal combustion engine having a stud mounted rocker arranged in accordance with the invention. The section is taken on line 11 of FIGURE 3.

FIGURE 2 is a fragmental side view of such an engine as seen from the right side of FIGURE 1, showing three such rockers and with the push rods of the outboard rockers oppositely inclined and interconnected at their upper ends to prevent rotation of the rockers about the supporting studs.

FIGURE 3 is a plan view as seen in the direction of the arrows 33 in FIGURE 2.

Referring now in detail to the drawing, an internal combustion engine is shown having a cylinder head 1 and cylinder block structure 2. Extending above the cylinder head are a series of studs 3, 4 and 5, supporting rockers 6, 7 and 8, respectively, In the particular engine shown, the outboard rockers 6 and 8 each operate a poppet valve, that operated by the rocker 6 being shown at 9 in FIG- URE 1. The similar valve (not shown) operated by the "ice rocker 8 and the valve 9 are exhaust valves for opening and closing ports in the cylinder head, that port controlled by the valve 9 being indicated at 10 in FIGURE 1. The middle rocker 7 may also be used to operate another poppet valve or, as in the particular engine shown, a fuel injector indicated generally by the numeral 11. Each of the valves as well as the fuel injector are biased closed by a coil spring such as shown at 12 in FIGURE 1, and movement of the rockers in opposition to their springs is effected by push rods 13, 14 and 15. Pivotal connections at the upper ends of the push rods are shown in-the form of balls 16, 17 and 18 which abut the adjacent ends of their respective rockers, and the lower ends of the push rods 'bear against tappets shown in the form of roller followers 19, 20 and 21 engaging the cam shaft 22 of the engine.

The studs extend through the respective rockers at their fulcrums, there being an opening such as shown at 23 (FIGURE 1) in each rocker with sufficient clearance to accommodate its full rocking movement. Each rocker is journaled on its stud by hearing means in the form of an annular member 24 through which the upper end of the stud extends, and these bearing members and the opposing surfaces 25 of the rockers are generally spherical in shape to accommodateboth rocking of the rocker and its rotation about the stud.

In conventional mountings of such rockers the bearing members 24 are retained in place on the stud by direct engagement with suitable thrust means such as a retaining nut 26, however in accordance with my invention 1 have interposed a cantilever spring 27 between each nut 26 and bearing 24. This spring has its free end extending longitudinally of the rocker toward the push rod end thereof and bears downwardly thereagainst to assist the coil return spring 12 in effecting return of the rocker after each operating stroke of its poppet valve or fuel injector. Since the fixed end of the cantilever spring is held by the stud, the point of contact A (FIGURE 1) of the free end of the spring with the rocker varies in distance from the stud during the rocking movement, thereby varying the rate of loading of the cantilever spring as it opposes the rocking movement. This varying rate increases to a maximum as the valve 9 or the fuel injector reaches its maximum open position. The rate of increase in biasing force of the cantilever spring is further augmented by forming the latter of a plurality of separate leaves 28, 29 and 30, with the successively shorter leaves being arranged on top of the longer leaves as shown.

One disadvantage of such stud mounted rockers journaled on spherically shaped bearing members of this type has been that special means must be provided to prevent rotation of the rockers about their respective studs and resultant disengagement from their push rods and their valves or fuel injectors which they are intended to actuate. This problem is obviated in accordance with my invention by using rockers of generally upwardly presenting channel shape whose respective side walls 31 and 32 closely embrace the sides of the cantilever springs 27. By suitably keying or otherwise securing the fixed ends of the springs against rotation on the studs, the free ends of the springs serve to cooperate with the side Walls 31, 32 of the rockers in limiting rotation of the rockers about the studs.

Also, where two such stud mounted rockers as shown at 6 and 8 in FIGURES 2 and 3 are operated in unison by push rods 13 and 15 which are oppositely and equally inclined from a plane B equidistant from the respective planes C and D of rocking movement of their rockers, the tendency of each rocker to so rotate about its stud may be counterbalanced by interconnecting the upper ends of the two push rods with a rigid member 33. This 3 i member 33 in the particular arrangement shown takes the form of a bar or plate rigidly connected as by welding at 34 to the respective balls Idand 18. Where the two push rods 13 and are arranged on opposite sides of an intermediate push rod 14 for a third rocker, the intermediate section of the member 33 is U-shaped and provided with a central aperture 35 to provide clearance for the intermediate push rod 14 and its rocker 7.

The cantilever spring means as described may thus take the place of a second coil spring arranged either concentrically of the coil spring shown at 12, or of a separate coil spring which in some engines is arranged about the push rod to act against its tappet follower (19, 2%) or 21) in maintaining engagement of the latter with the cam shaft 22. Also, While I have illustrated my stud mounted cantilever springs as associated with rockers for operating poppet valves and fuel injectors, obviously they can be used with equal advantage in biasing return movement of rockers which operate various other reciprocated means employed in engines and like machines. Thus, the invention is not to be limited other than by the scope of the appended claims.

I claim:

1. In combination with a rocker, a supporting stud therefor at the rocker fulcrum, bearing means on the stud journaling rocker movements of the rocker, thrust retain- 3. The combination of claim 2, together with an engine 35 cylinder head, means reciprocable in the head and drivingly connected to one end of said rocker, a return spring opposing movementof said reciprocable means in one direction, said cantilever spring having its free end extending from the stud in the direction to assist said return spring.

4. The combination of claim 1, wherein said cantilever spring comprises a plurality of spring leaves of different lengths with the longer of said leaves being the more adjacent the rocker, whereby the resisting force imposed by the cantilever spring in opposition to rocking movement of the rocker in said direction increases with increased movement of the rocker in said direction.

References Cited by the Examiner UNITED STATES PATENTS 1,227,812 5/1917 MacPherson 123 1,346,401 7/1920 Ellis 123-90 1,349,090 8/1920 Ohrt 74-519 1,363,060 12/1920 Shearer 128 90 1,728,149 9/1929 Berne 123 90 1,742,746 1/1930 Zubaty 74569 1,927,973 9/1933 Bull 267 1 2,113,656 4/1938 Kliesrath 267-19 2,707,945 5/1955 Hughes 123-90 2,909,936 10/1959 Huthsing'et al, 74-102 3,041,886 7/1962 Atherton 74-102 FOREIGN PATENTS 459,630 5/1928 Germany.

MARK NEWMAN, Primary Examiner.

RICHARD B. WILKINSON, KARL J. ALBRECHT,

Examiners.

A. L. SMITH, Assistant Examiner. 

1. IN COMBINATION WITH A ROCKER, A SUPPORTING STUD THEREFOR AT THE ROCKER FULCRUM, BEARING MEANS ON THE STUD JOURNALING ROCKER MOVEMENTS OF THE ROCKER, THRUST RETAINING MEANS ON THE STUD FOR SAID BEARING MEANS, AND A CANTILEVER SPRING SECURED TO THE STUD AND HAVING ITS FREE END RESILIENTLY ENGAGING THE ROCKER AT A DISTANCE LATERALLY OF THE STUD IN OPPOSITION TO ROCKING MOVEMENT OF THE ROCKER IN ONE DIRECTION. 